T-98 vs Arjun
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dabrownguy
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gf man did you d research? Arjun and Type 98 are very different from each other. The Arjun uses 120 mm barrel superior to the 125 mm used in the type 98. Not only is 120 mm barrel supperior but rifle gun is supperior to smoothbore. Arjun's turret is simmilar to Challenger 2 because noth use rifles that have twice the range of 125 mm smoothbore. Type 98's turret is comparable to that of t-90. Arjun wieghs 59 tons while the Chinese tanks at 49 tons. Type 98 has better laser defence but lacks the range and fire power given by the Arjun. I think we wil see indegnious engine of 15 000 hp which DRDO is developing with Russia in the Arjun MK2 and many other electronics and anti helecopter missiles.
The issue of smooth or rifled bore is one of what type of ammo is being used. There are some ammo types where a smoothbore is much better and vice versa. (HESH. HEAT, APSFD) etc...dabrownguy said:
15,000 hp will power a small patrol frigate - did you mean 1500hp?
Ammo types in rifle/smooth bores
Bits and pieces...
HESH requires a rifled barrel. HEAT works best from smoothbores. Brit Challengers use HESH rounds. they are changing to smoothbore, but that is to standardise the NATO fitouts.
HESH is not particularly good for anti-personel work due to its fragmentation properties, which are inferior to HE.
HESH is ideal for structures, light armor, etc.
HEAT is better for an anti-tank role, but you would probably use an APFSDS round instead anyway
The advantages of smoothbore are a longer barrel life, stronger usable propellents, cheaper to manufacture
HESH rounds require rifling. They are next to useless if they don't spin, hence no smoothbore HESH rounds.
One of the armour guys should be able to tell you more.
Its not a simple thing to say that smoothbores are better than rifled, they are not in a number of circumstances, it really gets down to army and armoured doctrine - the prosecution of war by an armoured division will be dictated by the overall armour strategy.
Bits and pieces...
HESH requires a rifled barrel. HEAT works best from smoothbores. Brit Challengers use HESH rounds. they are changing to smoothbore, but that is to standardise the NATO fitouts.
HESH is not particularly good for anti-personel work due to its fragmentation properties, which are inferior to HE.
HESH is ideal for structures, light armor, etc.
HEAT is better for an anti-tank role, but you would probably use an APFSDS round instead anyway
The advantages of smoothbore are a longer barrel life, stronger usable propellents, cheaper to manufacture
HESH rounds require rifling. They are next to useless if they don't spin, hence no smoothbore HESH rounds.
One of the armour guys should be able to tell you more.
Its not a simple thing to say that smoothbores are better than rifled, they are not in a number of circumstances, it really gets down to army and armoured doctrine - the prosecution of war by an armoured division will be dictated by the overall armour strategy.
elkaboingo
New Member
Re: Ammo types in rifle/smooth bores
an interesting thing about the HEAT rounds. you said they were anti tank but that sabot would be used anyways. that is correct. us tankers were using HEAT on lightly armored things and trucks, which was a big waste. i heard some talk that instead of using heat, they would fit a 20mm cannon in teh coax position. this would have the capability to take out lightly armored targets efficiently. :smokingc:gf0012 said:
yutong chen
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dabrownguy
Type 98 MBT was made to challenge the M1A1. Was Arjun made to challenge a M1A1? Didn't think so. By the way, i don't think Arjun have any laser defence :smokingc: Type 98 MBT can fire a ATGM which have way more range than Arjun.
Type 98 MBT was made to challenge the M1A1. Was Arjun made to challenge a M1A1? Didn't think so. By the way, i don't think Arjun have any laser defence :smokingc: Type 98 MBT can fire a ATGM which have way more range than Arjun.
dabrownguy
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yutong chen, corrections my friend. Type 98 was made to challenge soviets T-80 and than changed it to challenge M1A1 which I seriously doubt it could do because of 125 mm and light armor. And the ATGM on tanks are useless. They are for last defence and maximum range on those are probabily 5km while the Arjun's "rifled" gun can throw hesh rounds at 8km effectivaly. Type 98 costs 2 million compared to Arjun whos cost is 4.6 to 5.6 million each. And in orfer to use ATGM the tank has to stop that is why its a last resort. Arjun's gun can penatrate ALL NATO armor at 2.5 km distance with AFSPDS rounds with 100% result! which only leads me to conculde that soviet design armor with be dystroyed at 3.5kms with 100% results while maximum range could be 5 km. I never read a article comparing to M1A1 cause that is ridecoulous. ATGM are only good when on fast vehicles or helecopters. And the laser defence is nothing to be proud of when it would only be succesfull against helecopters. Arjun gun is superior to type 98, which is obvious and probabily superior to Leapords 120 mm smoothbore but I believe smoothbore is supperior because of the variety on ammonution. I don't see how Type 98 can be a challenge to M1A1 or A2. Theres a 20 ton difference in armor and majour differnce in guns. Arjun is the same speed as Challenger 2 but faster on roads with the 1500 hp engine. Thats right Arjun now uses a 1500 hp engine indenous developed, and the problem was solved in the MK1 versions. The German engine did not fit with the transmission and the indegnous engine is doing well for the army and 12 Arjuns are in service. And you are right that Arjun wasn't made to challenge Abrhams. The first Arjun prototype costed 1.6 million each with a 120 mm smoothbore but due to the armies demands they changed the design severel times. The Arjun costs 5.6 million because the engine and gun are the most expensive parts. Arjun wasn't meant to challenge Western tanks but it is now comparable in firepower,speed,meunarbility,everything. Type 98 can't last long against Abrhams! Tank battles are fought with many tanks and other vechiles and helecopters. DRDO never sought to put NAG on Arjun because BMP2 can carry the NAG and SAMs while Arjun can knock out other tanks. Arjun's range is the main advantage just like most western tanks. Type 98 was designed for numbers and easy to manufacture while the Arjun was comparabily hard to manufacture because components of the gun had to imported. Arjun also has majour Isreali tech. And by the way dont listen to propganda that compares Type 98 with Western tanks.
My list of best tanks.
Leapord 2-simply the best
M1A2-Armor is heavy and battle proven
Markeva 4-Isreali and latest American tach
Challenger 2-Rifled gun and tech.
Lecrlec-Frances best
Arjun-Rifled gun and tech
T-90-Japanese version with American tech, not related to T-90 (russia)
T-90-Russias improved T-80 and T-72 version. Superior to T-80 is everyway.
Type 98-Active laser defence.
T-80-One of the best
AK-For desert combat.
I personally this list right. If you think its wrong tell me.
My list of best tanks.
Leapord 2-simply the best
M1A2-Armor is heavy and battle proven
Markeva 4-Isreali and latest American tach
Challenger 2-Rifled gun and tech.
Lecrlec-Frances best
Arjun-Rifled gun and tech
T-90-Japanese version with American tech, not related to T-90 (russia)
T-90-Russias improved T-80 and T-72 version. Superior to T-80 is everyway.
Type 98-Active laser defence.
T-80-One of the best
AK-For desert combat.
I personally this list right. If you think its wrong tell me.
yutong chen
New Member
I don't know where you got the facts about Type 98's weight and the main gun. China doesn't declassify any active military hardware. In fact, China never showed its troops. The parade at any year are run by a bounch of soldiers trained for "demonstrations". India, on the other hand, is weak, which cannot keep secret from a superior nation such as US. Tanks from a poor country that are said too good to be true are published to confuse World Powers so they will think twice before attacking. Have you ever wondered why US takes China so seriously, and never really cares about India? China will be a 21st century USSR with a strong economy. 50 years, China came from a country like present day Iraq to a world power, what will happen in another 50 years?
without wanting to start a more robust exchange of "ours is better than yours" between proponents of these two platforms, the bottom line is that these 2 designs are a legacy of each countries war fighting doctrine.
They are both very very different tanks in design and capability that are relevant for the "extremis" of their perceived conflict participation.
They are both very very different tanks in design and capability that are relevant for the "extremis" of their perceived conflict participation.
dabrownguy
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http://www.sinodefence.com/army/tank/type98.asp, says right here that the tank is 50 tons compared to Arjuns 58.5 tons. And I don't know why you brought up media sensorship. The truth is in India the media always spys on IA and Ia gives aways vaulable secerts. IA isn't very secerative when it comes to regular military equipment, which country is? China doesn't hide standard military facts. And the US isn't afraid of India because we don't plan to challenge them, India just wans to grow. PRC is always talking about the US threat. The truth is PRC is worried about US and US don't give a rats @$$ about PRC. Its the American media my friend because fear of war sells. US could send PRC back 50 years but don't cause of China's ICBM. PRC plans to challenge the US, India on the other hand only sees the US as a potential ally against terroism. I really don't understand what you mean about papers saying tanks suck but Indian media always practices is right to critize the Indian military in everway. Indian media never said anything about Arjun being the greatest tank is the world. On the other hand Chinese media always sayz Type 98 is compared to Abrhams. And back to the topic. Arjun has atleast 5 ton more armor that is a fact. A 1500 hp engine. Rifled gun. And the Type 98 uses a 125 mm gun. GF0012 knows that 120 mm gun is supperior. 120 mm gives more penetration and more variety of ammo. 125 mm gun is only good if you have "new" high charge ammo, which unfortunatly Russia has; they just developed it. And it is a FACT that rifled gun is superior to smoothbore! Rifled guns are expensive. Thing is smoothbore can fire DU rounds. Most tank carry 10 or less DU rounds which are usaully 1-3 hit kill, depends on the tech. The rest of the ammos are smoke,AFPSDS or other. Now HESH rounds are useless which most tanks end up fireing most of the time. HESH rounds fired from a smoothbore weapon do not kill armor but when fired from a rifle which spins it, it becomes just as lethal as DU rounds. And AFSPDS ammo is at its maximum when fired from rifled guns.
dabrownguy
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you need to brush up on your tank knowledge.
Actually i will post something i keyed in earlier on a diffrent forum. i was having a argument with some lad. Questions are his and ans mine.
here it is:
Q) Sorry for stepping in, but i'm quite annoyed by people here keep saying a rifled tank gun is better while the fact is a smooth bore is obviously superior
Ans)…and that is why I keep saying that this Arjun rifled gun is a accidental find by Indian Engineer’s.
Lets take this point by point and in the process look at the deeper secret of rifled guns, development/advances in chromium lining[…gives increased velocity and therefore penetration power to the round, greater precision and reduced wear on the barrel.which is reduced to negligible amount in the Arjun…will explain below] and a Russian high charge shell specially designed for the 120 of Arjun.{sorry can’t say much on this due to classification of technology.}
Q1). The gas seal on a rifled round has to be metal-on-metal contact between the round and the barrel this has a high friction co-efficient -limiting acceleration (see chromium lining as mentioned above) of the rifled round.
Ans] Wrong - overcome by advances in chromium lining and here is what’s new- rounds fired through this 120 are specially designed to reduce friction. This is true for FS-AP and the high power round they developed with the Russians. So rounds fired are a) HesH, b) FS-AP and c) special ammo for high range high impact tank busting (more like a SPIN stabilized round)
Q) On a fin-stabilized round the gas seal can be plastic etc (any suitable low friction material). There are no edges inside the barrel to inhibit acceleration (rifling). So more energy is expended accelerating the round.
Ans] Ok 100% correct (you are saying: “rifling does increase range and accuracy but actually decreases muzzle velocity. As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit – and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration. The griping by rifling is thus removed from the concept of FS-AP shots…long rod and otherwise. Also note that the “Greenhill's Rule†is pushed to its limits through research. This is a significant contribution of Arjun 120mm to the MBT’s of the world…if ever the tech is declassified. Our Israli council is working on tech transfer for the same.
…and that’s the reason I had said in my earlier post the British and even the American’s would be interested in this barrel and tech. Apparently these chaps seem to be better in not just software. Believe me I had my opinions about rifling before I saw what I saw.
The reason I didn’t post was because I did’nt have people with your knowledge to share it with.
Q2). The ability to fire a differnt types of ammunitions. This includes missiles and long rod penetrators. (long rod penetrators are long rod like ammunition designed to punch through armour like a "dart". This type of ammunition cannot be spin stablised because the spinning will break the long projectile)
Ans) Missiles are not required by long range powerful guns. Are you saying rifled barrels don’t fire long rods??? Because the do, what do you think the CHARM ammo is! The AP for Arjun is long-rod type. Yes correct spin will break the long rod projectile….again chromium lining and condom’sing the cone was the answer. The spin is actually reduced to extremely slow spin to a point of being negligible …not like a bullet. But note that the Arjun 120mm barrel is one of the most expensive parts of the tank.
Q3). While a rifled helps to stabilise the shell by spinning, it does subject the round to precession. This means the point tends to wander in a small circle. This is less than desirable when you want to punch a hole through armour by brute force.
Ans) same as point 2. Though you are conventionally correct.
Q4). Less wear and tear for smooth bores
While a shell from a rifled gun is marginally more stable over long ranges, this is nothing when compared to the importance of the Fire Control System. With a good FCS, the effect of wind speed and such can be compensated so a fin stablised round can be just as accurate as a spin stablised round.
When we talk about range for tank gun, we talk about the maximum range that the shell can still penetrate enemy armour. In this aspect, a smooth bore gun has better effective range.
Ans) I think these are answered by reading above. Also the “EFFECTIVE†range is of Smooth bore is challenged by rifled hyper velocity long rods which don’t compromise on muzzle velocity and thereby give long effective range.
Q5)Just look at the most modern MBTs in the world, everyone of them saves our own challenger is using a smooth bore gun. Plus our army is talking about switching to smooth bore guns for the challenger 2'sreplacement.
Ans) Correct. The reason why this is a so is due to R&D into various forms of ammo and the diversity achieved in ammo’s and standardization to NATO and cheaper production costs of conventional shells. This is not possible via Rifled guns. The Arjun is designed for this continent with specific objectives and the 3 type ammunition variety more than meet the required demand of the Indian Army. The ground displacement is good, mobility, sensors, crew comfort and ease of driving Superior firepower - to destroy targets (tank/bunker’s) and very good Armour protection.
I would also like to add that Arjun had its 120mm barrel pop out during trials of the Russian high charge ammo about 2 years ago – as told to me.
P.S: With developments like the german L55 and DM 53 developments maybe Rifling will have to be droped and smooth bore re-adopted. I guess when R&D started with the Indian's the rifled looked more promising....lets see, time will tell
I got this from another forum. The guy goes by the name of Denil. Tank Xpert
Actually i will post something i keyed in earlier on a diffrent forum. i was having a argument with some lad. Questions are his and ans mine.
here it is:
Q) Sorry for stepping in, but i'm quite annoyed by people here keep saying a rifled tank gun is better while the fact is a smooth bore is obviously superior
Ans)…and that is why I keep saying that this Arjun rifled gun is a accidental find by Indian Engineer’s.
Lets take this point by point and in the process look at the deeper secret of rifled guns, development/advances in chromium lining[…gives increased velocity and therefore penetration power to the round, greater precision and reduced wear on the barrel.which is reduced to negligible amount in the Arjun…will explain below] and a Russian high charge shell specially designed for the 120 of Arjun.{sorry can’t say much on this due to classification of technology.}
Q1). The gas seal on a rifled round has to be metal-on-metal contact between the round and the barrel this has a high friction co-efficient -limiting acceleration (see chromium lining as mentioned above) of the rifled round.
Ans] Wrong - overcome by advances in chromium lining and here is what’s new- rounds fired through this 120 are specially designed to reduce friction. This is true for FS-AP and the high power round they developed with the Russians. So rounds fired are a) HesH, b) FS-AP and c) special ammo for high range high impact tank busting (more like a SPIN stabilized round)
Q) On a fin-stabilized round the gas seal can be plastic etc (any suitable low friction material). There are no edges inside the barrel to inhibit acceleration (rifling). So more energy is expended accelerating the round.
Ans] Ok 100% correct (you are saying: “rifling does increase range and accuracy but actually decreases muzzle velocity. As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit – and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration. The griping by rifling is thus removed from the concept of FS-AP shots…long rod and otherwise. Also note that the “Greenhill's Rule†is pushed to its limits through research. This is a significant contribution of Arjun 120mm to the MBT’s of the world…if ever the tech is declassified. Our Israli council is working on tech transfer for the same.
…and that’s the reason I had said in my earlier post the British and even the American’s would be interested in this barrel and tech. Apparently these chaps seem to be better in not just software. Believe me I had my opinions about rifling before I saw what I saw.
The reason I didn’t post was because I did’nt have people with your knowledge to share it with.
Q2). The ability to fire a differnt types of ammunitions. This includes missiles and long rod penetrators. (long rod penetrators are long rod like ammunition designed to punch through armour like a "dart". This type of ammunition cannot be spin stablised because the spinning will break the long projectile)
Ans) Missiles are not required by long range powerful guns. Are you saying rifled barrels don’t fire long rods??? Because the do, what do you think the CHARM ammo is! The AP for Arjun is long-rod type. Yes correct spin will break the long rod projectile….again chromium lining and condom’sing the cone was the answer. The spin is actually reduced to extremely slow spin to a point of being negligible …not like a bullet. But note that the Arjun 120mm barrel is one of the most expensive parts of the tank.
Q3). While a rifled helps to stabilise the shell by spinning, it does subject the round to precession. This means the point tends to wander in a small circle. This is less than desirable when you want to punch a hole through armour by brute force.
Ans) same as point 2. Though you are conventionally correct.
Q4). Less wear and tear for smooth bores
While a shell from a rifled gun is marginally more stable over long ranges, this is nothing when compared to the importance of the Fire Control System. With a good FCS, the effect of wind speed and such can be compensated so a fin stablised round can be just as accurate as a spin stablised round.
When we talk about range for tank gun, we talk about the maximum range that the shell can still penetrate enemy armour. In this aspect, a smooth bore gun has better effective range.
Ans) I think these are answered by reading above. Also the “EFFECTIVE†range is of Smooth bore is challenged by rifled hyper velocity long rods which don’t compromise on muzzle velocity and thereby give long effective range.
Q5)Just look at the most modern MBTs in the world, everyone of them saves our own challenger is using a smooth bore gun. Plus our army is talking about switching to smooth bore guns for the challenger 2'sreplacement.
Ans) Correct. The reason why this is a so is due to R&D into various forms of ammo and the diversity achieved in ammo’s and standardization to NATO and cheaper production costs of conventional shells. This is not possible via Rifled guns. The Arjun is designed for this continent with specific objectives and the 3 type ammunition variety more than meet the required demand of the Indian Army. The ground displacement is good, mobility, sensors, crew comfort and ease of driving Superior firepower - to destroy targets (tank/bunker’s) and very good Armour protection.
I would also like to add that Arjun had its 120mm barrel pop out during trials of the Russian high charge ammo about 2 years ago – as told to me.
P.S: With developments like the german L55 and DM 53 developments maybe Rifling will have to be droped and smooth bore re-adopted. I guess when R&D started with the Indian's the rifled looked more promising....lets see, time will tell
I got this from another forum. The guy goes by the name of Denil. Tank Xpert
To be fair, I wouldn't say that HESH rounds are absolutely useless, HESH was used against Iraqi T-55/62/69 tanks in desert storm.
The longest recorded tank-against-tank kill in history was recorded by a Challenger firing HESH in that conflict (5,200 meters).
The other thing is that NATO standardisation to a 125mm gun could indicate that they believe that the 120mm rifled gun has been maxed out in its development. Of course this can change with the right ammo mix - its a matter of whether some countries will persist in trying to make more effective ammo rather than go to a larger calibre.
The longest recorded tank-against-tank kill in history was recorded by a Challenger firing HESH in that conflict (5,200 meters).
The other thing is that NATO standardisation to a 125mm gun could indicate that they believe that the 120mm rifled gun has been maxed out in its development. Of course this can change with the right ammo mix - its a matter of whether some countries will persist in trying to make more effective ammo rather than go to a larger calibre.
dabrownguy
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- #73
Is that the Challenger that uses rifled gun?
gf there are things I would not agree with. NATO knows 120 mm is superior. For somereason that even NATO doesn't now the 120 mm turret gets more penetration and range. And 120 mm is also used because of technology availability.
gf there are things I would not agree with. NATO knows 120 mm is superior. For somereason that even NATO doesn't now the 120 mm turret gets more penetration and range. And 120 mm is also used because of technology availability.
dabrownguy
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I'm not gonna respond for a while so heres something to ponder and read about.
http://www.globalsecurity.org/military/world/india/arjun.htm
Arjun
At the end of the 1971 war, the Indian army realized the limitations of their tank fleet in the harsh desert conditions of Rajasthan, a northwestern Indian state bordering Pakistan, so they initiated their own MBT design. The Main Battle Tank (MBT) occupies a pivotal role in the present day battle field on account of its ability to provide accurate fire power with cross country mobility, reasonable protection from conventional and nuclear threats and flexible response to changing battle situations.
In order to eliminate dependence on foreign countries for design and manufacture of Armoured Fighting Vehicles (AFV) and to place the country on par with super powers with regard to quality of tanks and also to eliminate completely the requirement of foreign exchange (FE) in the production of tanks, Government in May 1974 sanctioned a project for design and development of MBT by Defence Research and Development Organisation (DRDO) at a total cost of Rs 15.50 crore (FE Rs 3.70 crore). The tanks were to be in service during 1985 to 2000 AD and were in replacement of existing tanks which were expected to be out-dated beyond 1985.
The first “Arjun†(named after a mythical Hindu warrior prince) concept was laid out in 1974 by the Combat Vehicles Research and Development Establishment (CVRDE) of the Defence Research and Development Organization (DRDO). Based on 1971 battlefield experiences, the Arjun would have a locally-designed, rifled 120mm main gun, a German, MTU-based diesel powerplant (The Indians consider turbine engines fuel guzzlers), and a computerized fire control system with a laser rangefinder.
The Main Battle Tank Project sanctioned in May 1974 envisaged bulk production by April 1984. However this time frame was not adhered to and was revised from time to time and bulk production was to commence from 1990 onwards but even the revised time frame could not be adhered to. As per time frame fixed in May 1974, four mild steel prototypes were to be offered for trials by April 1980 and eight armoured prototypes by April 1982. Trickle production was due to commence by April 1983 and bulk production by April 1984. This schedule was revised from time to time.
One of the early Arjun prototypes was unveiled in April 1985, with a number of prototypes undergoing technical testing while desert trials were scheduled for that summer. At the time, it was reported to have a 120mm smooth-bore main gun and would use a 1400-hp MTU-based diesel until an indigenous one was ready. Weight would be about 50 tons, and the tank would cost about $1.6 million (U.S.). Development costs rose about 500 percent throughout the ’80s, and through a development process plagued with delays, the end product visually resembles the German Leopard II, however, unlike the German vehicle, its future remains in doubt.
A total of 12 MK-I prototypes based on imported propulsion unit, seven MK-II prototypes with indigenous propulsion were to be delivered by June 1987 and June 1990 respectively; 23 MK-I, PPS tanks by December 1988 and bulk production was to commence from 1990 onwards. As against this, 12 MK-I prototypes with imported propulsion were produced by February 1989 and 15 MK-I PPS tanks upto December 1996. MK-II type prototype were not expected to be ready in the near future on account of the delays in the development of the indigenous engine.
The automotive trials of two prototypes carried out by Army during 1988-89 revealed major deficiencies. The Army, therefore, on 26 July 1989 wanted these deficiencies to be sorted out before commencement of production of pre-production series (PPS). However, on 31 July 1989 Ministry decided to place orders for the production of PPS tanks. Two fully integrated prototypes were given to the Army for full fledged evaluation only in March 1990 after the commencement of production of PPS tanks. The evaluation trials of the prototypes also revealed major deficiencies. Subsequent trials were conducted on PPS tanks. Till July 1997, 15 pre-production series tanks which were subjected to extensive user and troop trials failed to meet fully even the bottom line parameters of the user.
As of mid-2000 India planned to acquire T-90 tanks, based on field trials which had already been completed. Although orders had been placed for the supply of 124 Arjun tanks through the Defence Research Development Organisation, it would be difficult to predict when these orders would be fufilled. Until such time, T-90 tanks would serve to counter Pakistan's T-85 tanks.
Pakistan’s announcment in 1995 of a deal with Ukraine to purchase T-84s caused a flurry of activity in the Indian tank development community. And on 9 January 1996, the Arjun was formally unveiled and cleared for mass production. Further improvements were deemed necessary even after the Arjun design profile was accepted again in July 1996. On 27 August 1996, the Defense Production and Supplies Secretary ordered 15 pre-production tanks from the Heavy Vehicles Factory, Avadi (at which point, estimates placed the project cost at $112 million).
The Summer trials carried out in April 1997 on PPS-15, reference tank for bulk production indicated that though there was improvement from the previous years, it was still below the acceptable standards. The major deficiencies pointed out in the summer trials of 1996 i.e. accuracy of gun at battle ranges, mission reliability, lethality of ammunition, containerisation of ammunition bin, emergency traverse etc. continue to persist and were yet to be solved. The Army accordingly indicated in July 1997 that in its present form, the overall reliability of MBT Arjun was far from satisfactory. The Army further indicated that periodic failures of equipment and subsystems tend to reduce the confidence level of troops. The Army also observed that the aspect of armour protection had not been tried out.Army recommended in June 1997 that Limited Series Production should commence only after all the observations and shortcomings noticed were rectified and shown to them.
As of mid-1997 the list of faults after 20 years of development was not encouraging. In addition to numerous technical modifications to its fire and gun control systems, the fire control system in particular has been found unable to perform in temperatures above 42 degrees Celsius (108° F). The DRDO has been considering scrapping the current Arjun fire control system in favor of whatever is accepted for the T-72M1 upgrade program. Defects noticed during the user trials of the Arjun Mk.1 MBT, including over-heating of the engine in Rajasthan desert areas, had supposedly been “by and large overcome†while other complaints were being addressed.
MBT Arjun in its present form will require increased maintenance time and efforts-says the Army. The Army accordingly expressed grave concern on the reliability and maintainability of MBT and pointed out that while the world over the trend was to reduce the maintenance time, it had increased with MBT Arjun. According to DRDO, the views expressed by the Army are only a subjective opinion and the analysis of data shows an upward trend in mean time between failures (MTBF) over the years. DRDO have pointed out that trials carried out clearly brought out the efficiency/improvements effected in weapon system and in the automotive area ability to cover the required range in the stipulated time was also proved. They further contended that there is no overheating of the engine in desert conditions. Summer trials of 1997 indicated that the performance was below the acceptable standards.
Considered comparable to the M1A2 Abrams, Leopard 2, and Leclerc, the 59-ton "15th Variant" can achieve a maximum speed of 70 kph (55 mph) and cross-country speed of 40 kph with its 1400-hp powerplant. The 1,610-liter fuel tank allows for a cruising range of 200 km (120 miles). To ensure crew survivability, production versions will have the indigenously-researched and developed ‘Kanchan’ composite armor, an automatic fire detection and suppression system, and an NBC protection system designed and built by the Bhabha Atomic Research Center.
The rifled 120mm gun, which includes a muzzle reference system, is made of ESR steel and is fitted with a thermal sleeve and fume extractor. All main gun rounds use a semi-combustible cartridge case with increased energy propellant for higher muzzle velocity and greater penetration characteristics. In addition to the usual suite of rounds, an anti-helicopter round is under development as well. The Arjun’s fire control system includes a laser rangefinder, ballistic computer, thermal imaging night sight, stabilized panoramic sight for the tank commander, and a secondary telescopic sight. The LRF (integral to the gunner’s sight) has a range of nearly 10 km and a thermal imager (which can “seeâ€â€™ at around 5.5 km, recognize a target at 3.1 km and identify targets at 2.5 km). The Arjun fire control system’s ability to fire on the move during the night is a major step forward for Indian armored forces.
The Chassis and Automative System of MBT Arjun comprises main chassis, power pack (1400 HP engine coupled to hydromech transmission), running gear with hydropneumatic suspension, integrated fuel system, advanced electrical system and other dedicated special systems like integrated fire detection and suppression system. The chassis is fabricated from rolled homogenous armour plate using advanced welding technique. Frontal armour is of Kanchan composite sandwitched between armour plates. This fully integrated Arjun chassis and Automative System having smooth riding characteristics can be used as a mobile platform for any advanced weapon system. An extremely effective hydropneumatic suspension system has been developed for MBT Arjun. The suspension is externally mounted and provides vehicle springing and damping. It consists of one bogey wheel pair for each suspension station. Gaseous medium in the hydropneumatic suspension is for all terrain maneuverability for exploiting the power available. Casing and hub of the hydropneumatic suspension are sealed for preventing dust ingression and water seepage into the casing during operation in marshy area or shallow/medium fording. The MBT Arjun is fitted with double-pin steel track with detachable rubber pads. It is made out of steel casting having two bores for insertion of rubberised pins. It is an integral piece incorporating guide horns and has got a provision for insertion of detachable pads. The end connectors are induction-hardened in the area which comes in contact with the sprocket teeth to prevent wear.
As the indigenous efforts to develop a suitable engine and transmission system for the MBT were beset with problems, 42 power packs with transmission units were imported between November 1983 and 1988 from Germany for use on the prototypes and PPS tanks. However, as the imported transmission system was designed to cater upto 60 tonne load as against the all-up weight of 61.5 tonne for the MBT, a mismatch had arisen between engine and transmission which had resulted in bulging of side walls of the hull.
The integrated fire and explosion suppression system developed for MBT Arjun is based on state-of-the-art technology. The indigenous development of this system is considered to be a breakthrough in the field of fire protection engineering. It is capable of suppressing hydrocarbon fuel fire/explosion resulting from an enemy hit on the tank or due to any malfunctioning of the engine, transmission or any electrical short circuiting. The system is based on infra-red detectors for the detection of fire/explosion in the crew compartment of the battle tank and a continuous type of linear thermal detector popularly known as fire-wire for the engine compartment. Halon-1301 has been employed as a fire extinguishing medium. The system is capable of detection and suppression of hydrocarbon fuel fire/explosion in the crew compartment within 200 milliseconds and in the engine compartment within 15 s thereby enhancing the chances of survivability of the crew and battle effectiveness of the tank.
The first 120 tanks to be built would cost $4.2 million each, while other cost estimates places the figure at $5.6 million each per tank by 2001, given a purchase of 124 tanks to equip two regiments. Production of the first batch of tanks might take more than the planned five years, given the capacity at the Avadi factory.
Planned Arjun variants include mobile assault guns, an observation post vehicle, an air defense (gun or missile) version, a recovery vehicle, an engineer vehicle, and bridgelayers. New bridgelayers and recovery vehicles were necessary, given the Arjun’s substantial weight increase over the T-72M1 series.
Specifications
ARJUN Mk 1 (15th Preproduction Model)
Weight 59 tons (58.5 tonnes)
Length (gun forwards) 10.19m
Width (over tracks) 3.5m
(w/ skirts) 3.85m
Height (w/o 12.7mm AAMG) 2.32m
Engine 1400 HP MTU 838 Ka 501Diesel
Transmission Semi-automatic with 4 forward and 2 reverse gears.(also reported as ZF automatic)
Fuel 1610 ltrs
PERFORMANCE
Max Speed 72-70 kph (55 mph)
Cross Country Speed 40 kph
Cruising Range 200 km (120 miles)
Ground Pressure . 84 kg/cm Square
Ground Clearance .45m
Slide Slope: 60%
Climbing Gradient 35°
Trench 2.43 m (also given as 3m)
Vertical Obstacle .9m
Ford 1.4 m
ARMAMENT
Main Gun 120mm, stabalized w/ MRS (APFSDS, HE, HEAT, HESH and smoke)
12.7mm AA Gun (probably NVST)
7.62mm Coax (probably PK-T)
2 X 9 Smoke Grenade Launchers
LRF Range 10 km
Sights Thermal (Max Rng 5.5 km)
Active and Passive
Defensive Systems 'Arena' a possibilty, probable Laser Warning System
http://www.globalsecurity.org/military/world/india/arjun.htm
Arjun
At the end of the 1971 war, the Indian army realized the limitations of their tank fleet in the harsh desert conditions of Rajasthan, a northwestern Indian state bordering Pakistan, so they initiated their own MBT design. The Main Battle Tank (MBT) occupies a pivotal role in the present day battle field on account of its ability to provide accurate fire power with cross country mobility, reasonable protection from conventional and nuclear threats and flexible response to changing battle situations.
In order to eliminate dependence on foreign countries for design and manufacture of Armoured Fighting Vehicles (AFV) and to place the country on par with super powers with regard to quality of tanks and also to eliminate completely the requirement of foreign exchange (FE) in the production of tanks, Government in May 1974 sanctioned a project for design and development of MBT by Defence Research and Development Organisation (DRDO) at a total cost of Rs 15.50 crore (FE Rs 3.70 crore). The tanks were to be in service during 1985 to 2000 AD and were in replacement of existing tanks which were expected to be out-dated beyond 1985.
The first “Arjun†(named after a mythical Hindu warrior prince) concept was laid out in 1974 by the Combat Vehicles Research and Development Establishment (CVRDE) of the Defence Research and Development Organization (DRDO). Based on 1971 battlefield experiences, the Arjun would have a locally-designed, rifled 120mm main gun, a German, MTU-based diesel powerplant (The Indians consider turbine engines fuel guzzlers), and a computerized fire control system with a laser rangefinder.
The Main Battle Tank Project sanctioned in May 1974 envisaged bulk production by April 1984. However this time frame was not adhered to and was revised from time to time and bulk production was to commence from 1990 onwards but even the revised time frame could not be adhered to. As per time frame fixed in May 1974, four mild steel prototypes were to be offered for trials by April 1980 and eight armoured prototypes by April 1982. Trickle production was due to commence by April 1983 and bulk production by April 1984. This schedule was revised from time to time.
One of the early Arjun prototypes was unveiled in April 1985, with a number of prototypes undergoing technical testing while desert trials were scheduled for that summer. At the time, it was reported to have a 120mm smooth-bore main gun and would use a 1400-hp MTU-based diesel until an indigenous one was ready. Weight would be about 50 tons, and the tank would cost about $1.6 million (U.S.). Development costs rose about 500 percent throughout the ’80s, and through a development process plagued with delays, the end product visually resembles the German Leopard II, however, unlike the German vehicle, its future remains in doubt.
A total of 12 MK-I prototypes based on imported propulsion unit, seven MK-II prototypes with indigenous propulsion were to be delivered by June 1987 and June 1990 respectively; 23 MK-I, PPS tanks by December 1988 and bulk production was to commence from 1990 onwards. As against this, 12 MK-I prototypes with imported propulsion were produced by February 1989 and 15 MK-I PPS tanks upto December 1996. MK-II type prototype were not expected to be ready in the near future on account of the delays in the development of the indigenous engine.
The automotive trials of two prototypes carried out by Army during 1988-89 revealed major deficiencies. The Army, therefore, on 26 July 1989 wanted these deficiencies to be sorted out before commencement of production of pre-production series (PPS). However, on 31 July 1989 Ministry decided to place orders for the production of PPS tanks. Two fully integrated prototypes were given to the Army for full fledged evaluation only in March 1990 after the commencement of production of PPS tanks. The evaluation trials of the prototypes also revealed major deficiencies. Subsequent trials were conducted on PPS tanks. Till July 1997, 15 pre-production series tanks which were subjected to extensive user and troop trials failed to meet fully even the bottom line parameters of the user.
As of mid-2000 India planned to acquire T-90 tanks, based on field trials which had already been completed. Although orders had been placed for the supply of 124 Arjun tanks through the Defence Research Development Organisation, it would be difficult to predict when these orders would be fufilled. Until such time, T-90 tanks would serve to counter Pakistan's T-85 tanks.
Pakistan’s announcment in 1995 of a deal with Ukraine to purchase T-84s caused a flurry of activity in the Indian tank development community. And on 9 January 1996, the Arjun was formally unveiled and cleared for mass production. Further improvements were deemed necessary even after the Arjun design profile was accepted again in July 1996. On 27 August 1996, the Defense Production and Supplies Secretary ordered 15 pre-production tanks from the Heavy Vehicles Factory, Avadi (at which point, estimates placed the project cost at $112 million).
The Summer trials carried out in April 1997 on PPS-15, reference tank for bulk production indicated that though there was improvement from the previous years, it was still below the acceptable standards. The major deficiencies pointed out in the summer trials of 1996 i.e. accuracy of gun at battle ranges, mission reliability, lethality of ammunition, containerisation of ammunition bin, emergency traverse etc. continue to persist and were yet to be solved. The Army accordingly indicated in July 1997 that in its present form, the overall reliability of MBT Arjun was far from satisfactory. The Army further indicated that periodic failures of equipment and subsystems tend to reduce the confidence level of troops. The Army also observed that the aspect of armour protection had not been tried out.Army recommended in June 1997 that Limited Series Production should commence only after all the observations and shortcomings noticed were rectified and shown to them.
As of mid-1997 the list of faults after 20 years of development was not encouraging. In addition to numerous technical modifications to its fire and gun control systems, the fire control system in particular has been found unable to perform in temperatures above 42 degrees Celsius (108° F). The DRDO has been considering scrapping the current Arjun fire control system in favor of whatever is accepted for the T-72M1 upgrade program. Defects noticed during the user trials of the Arjun Mk.1 MBT, including over-heating of the engine in Rajasthan desert areas, had supposedly been “by and large overcome†while other complaints were being addressed.
MBT Arjun in its present form will require increased maintenance time and efforts-says the Army. The Army accordingly expressed grave concern on the reliability and maintainability of MBT and pointed out that while the world over the trend was to reduce the maintenance time, it had increased with MBT Arjun. According to DRDO, the views expressed by the Army are only a subjective opinion and the analysis of data shows an upward trend in mean time between failures (MTBF) over the years. DRDO have pointed out that trials carried out clearly brought out the efficiency/improvements effected in weapon system and in the automotive area ability to cover the required range in the stipulated time was also proved. They further contended that there is no overheating of the engine in desert conditions. Summer trials of 1997 indicated that the performance was below the acceptable standards.
Considered comparable to the M1A2 Abrams, Leopard 2, and Leclerc, the 59-ton "15th Variant" can achieve a maximum speed of 70 kph (55 mph) and cross-country speed of 40 kph with its 1400-hp powerplant. The 1,610-liter fuel tank allows for a cruising range of 200 km (120 miles). To ensure crew survivability, production versions will have the indigenously-researched and developed ‘Kanchan’ composite armor, an automatic fire detection and suppression system, and an NBC protection system designed and built by the Bhabha Atomic Research Center.
The rifled 120mm gun, which includes a muzzle reference system, is made of ESR steel and is fitted with a thermal sleeve and fume extractor. All main gun rounds use a semi-combustible cartridge case with increased energy propellant for higher muzzle velocity and greater penetration characteristics. In addition to the usual suite of rounds, an anti-helicopter round is under development as well. The Arjun’s fire control system includes a laser rangefinder, ballistic computer, thermal imaging night sight, stabilized panoramic sight for the tank commander, and a secondary telescopic sight. The LRF (integral to the gunner’s sight) has a range of nearly 10 km and a thermal imager (which can “seeâ€â€™ at around 5.5 km, recognize a target at 3.1 km and identify targets at 2.5 km). The Arjun fire control system’s ability to fire on the move during the night is a major step forward for Indian armored forces.
The Chassis and Automative System of MBT Arjun comprises main chassis, power pack (1400 HP engine coupled to hydromech transmission), running gear with hydropneumatic suspension, integrated fuel system, advanced electrical system and other dedicated special systems like integrated fire detection and suppression system. The chassis is fabricated from rolled homogenous armour plate using advanced welding technique. Frontal armour is of Kanchan composite sandwitched between armour plates. This fully integrated Arjun chassis and Automative System having smooth riding characteristics can be used as a mobile platform for any advanced weapon system. An extremely effective hydropneumatic suspension system has been developed for MBT Arjun. The suspension is externally mounted and provides vehicle springing and damping. It consists of one bogey wheel pair for each suspension station. Gaseous medium in the hydropneumatic suspension is for all terrain maneuverability for exploiting the power available. Casing and hub of the hydropneumatic suspension are sealed for preventing dust ingression and water seepage into the casing during operation in marshy area or shallow/medium fording. The MBT Arjun is fitted with double-pin steel track with detachable rubber pads. It is made out of steel casting having two bores for insertion of rubberised pins. It is an integral piece incorporating guide horns and has got a provision for insertion of detachable pads. The end connectors are induction-hardened in the area which comes in contact with the sprocket teeth to prevent wear.
As the indigenous efforts to develop a suitable engine and transmission system for the MBT were beset with problems, 42 power packs with transmission units were imported between November 1983 and 1988 from Germany for use on the prototypes and PPS tanks. However, as the imported transmission system was designed to cater upto 60 tonne load as against the all-up weight of 61.5 tonne for the MBT, a mismatch had arisen between engine and transmission which had resulted in bulging of side walls of the hull.
The integrated fire and explosion suppression system developed for MBT Arjun is based on state-of-the-art technology. The indigenous development of this system is considered to be a breakthrough in the field of fire protection engineering. It is capable of suppressing hydrocarbon fuel fire/explosion resulting from an enemy hit on the tank or due to any malfunctioning of the engine, transmission or any electrical short circuiting. The system is based on infra-red detectors for the detection of fire/explosion in the crew compartment of the battle tank and a continuous type of linear thermal detector popularly known as fire-wire for the engine compartment. Halon-1301 has been employed as a fire extinguishing medium. The system is capable of detection and suppression of hydrocarbon fuel fire/explosion in the crew compartment within 200 milliseconds and in the engine compartment within 15 s thereby enhancing the chances of survivability of the crew and battle effectiveness of the tank.
The first 120 tanks to be built would cost $4.2 million each, while other cost estimates places the figure at $5.6 million each per tank by 2001, given a purchase of 124 tanks to equip two regiments. Production of the first batch of tanks might take more than the planned five years, given the capacity at the Avadi factory.
Planned Arjun variants include mobile assault guns, an observation post vehicle, an air defense (gun or missile) version, a recovery vehicle, an engineer vehicle, and bridgelayers. New bridgelayers and recovery vehicles were necessary, given the Arjun’s substantial weight increase over the T-72M1 series.
Specifications
ARJUN Mk 1 (15th Preproduction Model)
Weight 59 tons (58.5 tonnes)
Length (gun forwards) 10.19m
Width (over tracks) 3.5m
(w/ skirts) 3.85m
Height (w/o 12.7mm AAMG) 2.32m
Engine 1400 HP MTU 838 Ka 501Diesel
Transmission Semi-automatic with 4 forward and 2 reverse gears.(also reported as ZF automatic)
Fuel 1610 ltrs
PERFORMANCE
Max Speed 72-70 kph (55 mph)
Cross Country Speed 40 kph
Cruising Range 200 km (120 miles)
Ground Pressure . 84 kg/cm Square
Ground Clearance .45m
Slide Slope: 60%
Climbing Gradient 35°
Trench 2.43 m (also given as 3m)
Vertical Obstacle .9m
Ford 1.4 m
ARMAMENT
Main Gun 120mm, stabalized w/ MRS (APFSDS, HE, HEAT, HESH and smoke)
12.7mm AA Gun (probably NVST)
7.62mm Coax (probably PK-T)
2 X 9 Smoke Grenade Launchers
LRF Range 10 km
Sights Thermal (Max Rng 5.5 km)
Active and Passive
Defensive Systems 'Arena' a possibilty, probable Laser Warning System
the next gen of challenger will use a rifled barrel. NATO is also standardising on using a rifled barrel. most of the reasons for the UK/NATO shift are due to data and results from Iraq.dabrownguy said:
the selection of 120 or 125 is really going to boil down to where those countries have done their threat assessment.
There are clearly reasons for the use of both. I'll see if I can get any info on why the shift.
The use of barrel launched GM's is usually considered to be a non useful application by western militaries, that is primarily because greater efficiencies could be realised out of using "dumb" munitions. The dynamics of this can obviously change if a smart barrel launched GM is developed. The germans, french, UK, US and the swiss certainly don't think so - that doesn't mean it isn't worthwhile per se, but certainly hasn't been deemed worthy enough of continued development by those nations.
The chinese may well have developed an efficient barrel launched GM. They are certainly capable of developing a useful solution even if it is not considered to be mature and viable by the west - but that gets down to an issue of continental doctrine etc...)
The issue for me would be, if you are going to turn the tank into a missile platform, then do it completely and make it a dedicated capability. AT this point you don't have a tank anymore, you have a missile based AFV crewed by "missileers" rather than "tankers".
120-125mm barrel snippets.
The 125mm shell is typically used by Russian and Chinese tanks
The reason for it over the 120mm was that the Russians were unable to build as tank barrels as strong as those in the the West (metallurgy issues in relation to mass production).
Therefore they couldn't fire 120mm shells that were as powerful as the standardised NATO ones. The "workaround" was to build 125 mm shells to gain extra power.
Rule of thumb: kinetic energy = mass x velocity squared, and thus speed is more important than mass. Velocity appears most important with sabots.
In real terms though the Russian/Soviet 125mm shells are still considered less powerful than NATO 120 mm, (assuming barrel length, ammo type are comparable)
I have taken the liberty of cutting and pasting from a poster I know who moderates a Tank and Armour forum. He is a master gunner, and was responsible for ammunition and gun development for the abrams, he also led the opening tank engagement in desert storm and has extensive respect accorded to him due to his common sense and balance (even by the ex russian tankers!)
/excerpt on
Okay, I guess a master gunner should answer this question and help with all the speculation. The Soviet 125mm gun (by the way, tank armament is a gun, not a cannon, for a bit of weapons trivia) is inferior in all aspects to the American M256 120mm gun. First issue is metallurgical technology, Russians are quite behind on that, and their main gun cannot fire a round equivalent to the sabot fired by an M1A1/A2. Because there is not as much propellant, the muzzle velocity is lower, decreasing accuracy. The advantage to a smoothbore gun is that you can fire rounds at very high velocity (upwards of 1600 m/s). This leads to a very stable ballistic trajectory. At lower velocities you are much better off with a rifled gun, where the spin will impart stability.
Next issue is something very technical called parallax. Basically, the bore of the gun and the gun sights can only point at the exact same place at one particular distance. Think of the line of sight from the sights and the gun as forming an X. You boresight your gun for a specific parallax range. If the enemy target is not precisely at that range, then the round fired will miss the aiming point by a few inches. This is not a problem if the ballistic trajectory is very stable, like APFSDS fired by an M1. If, however, the ballistic trajectory is unstable (for example the Russian 125mm gun at ranges beyond 1000 meters) parallax introduces a major accuracy problem. The Soviet army did not consider this to be an issue since combat in Western Europe tends to occur at ranges of 1000 meters or less due to the density of the urban terrain and mountains and forests.
Finally, as someone noted, kinetic energy, which is the primary means of killing a tank is determined by mass x velocity squared. But, the mass of a long rod penetrator has little do with the bore of the gun. The penetrator is typically no more than 40mm in diameter and 500mm in length. This basic design changes very little due to bore size. The American 105mm rifled gun fired a penetrator almost the same size as the American 120mm gun, albeit at a lower muzzle velocity. So, the reality is that the only way to increase the killing power and ballistic stability of the kinetic energy penetrator (sabot round) is by increasing the velocity. Since the Russian 125mm gun cannot withstand the amount of propellant required to do this it is at a disadvantage. This was seen clearly during Desert Storm in 1991 when American M1's engaged T-72's. The T-72 consistently missed targets beyond 1500 meters, while the M1 was successfully engaging beyond 3000 meters (I had first round hits at 3400 meters)
/excerpt off
Finally, this response is from a tanker with extensive experience in russian tanks and is the foreign equivalent of the prev poster (a US master gunner)
/excerpt on
The overall tolerances of gun making quality are much less strict that those in west in general.
Objectively looking, however, I wouldn't consider the accuracy of 125mm gun as dramatically worse as you suggest. Most of the limitations confronted are brought by inferior FC, not the gun itself (this is particularly true with Iraq tanks, though very poor crews in western standard and woefully outdated ammunition, 30 years old protection standards etc. also affected to their bad overall appereance). The problems brought by 125mm gun accuracy are significantly present at ranges over 3000 meters, i.e. ranges that they're not able to engage nearly as effectively as western tanks due to limitations of FC anyway. Only at ranges beyond 2500 meters the grouping of 125mm is such that it can cause a significant number of misses over frontal profile of a tank (higher than 1.3 of 125 vs. higher than 0.5 of 120). A qualified crew can achieve a very good hit percentage even with elder russian guns and sights at ranges up to 2000m. Unqualified crews, as seen on Iraqi case, can easily miss at ranges of 500m, which shouldn't happen
/excerpt off
The catch in the above is that the western development of the 125 cannot be associated with data history based on russian legacy weapons platforms. (remember the mass production metallurgy and qualitative metallurgy issues).
I hope this clears up some things for everyone.
The 125mm shell is typically used by Russian and Chinese tanks
The reason for it over the 120mm was that the Russians were unable to build as tank barrels as strong as those in the the West (metallurgy issues in relation to mass production).
Therefore they couldn't fire 120mm shells that were as powerful as the standardised NATO ones. The "workaround" was to build 125 mm shells to gain extra power.
Rule of thumb: kinetic energy = mass x velocity squared, and thus speed is more important than mass. Velocity appears most important with sabots.
In real terms though the Russian/Soviet 125mm shells are still considered less powerful than NATO 120 mm, (assuming barrel length, ammo type are comparable)
I have taken the liberty of cutting and pasting from a poster I know who moderates a Tank and Armour forum. He is a master gunner, and was responsible for ammunition and gun development for the abrams, he also led the opening tank engagement in desert storm and has extensive respect accorded to him due to his common sense and balance (even by the ex russian tankers!)
/excerpt on
Okay, I guess a master gunner should answer this question and help with all the speculation. The Soviet 125mm gun (by the way, tank armament is a gun, not a cannon, for a bit of weapons trivia) is inferior in all aspects to the American M256 120mm gun. First issue is metallurgical technology, Russians are quite behind on that, and their main gun cannot fire a round equivalent to the sabot fired by an M1A1/A2. Because there is not as much propellant, the muzzle velocity is lower, decreasing accuracy. The advantage to a smoothbore gun is that you can fire rounds at very high velocity (upwards of 1600 m/s). This leads to a very stable ballistic trajectory. At lower velocities you are much better off with a rifled gun, where the spin will impart stability.
Next issue is something very technical called parallax. Basically, the bore of the gun and the gun sights can only point at the exact same place at one particular distance. Think of the line of sight from the sights and the gun as forming an X. You boresight your gun for a specific parallax range. If the enemy target is not precisely at that range, then the round fired will miss the aiming point by a few inches. This is not a problem if the ballistic trajectory is very stable, like APFSDS fired by an M1. If, however, the ballistic trajectory is unstable (for example the Russian 125mm gun at ranges beyond 1000 meters) parallax introduces a major accuracy problem. The Soviet army did not consider this to be an issue since combat in Western Europe tends to occur at ranges of 1000 meters or less due to the density of the urban terrain and mountains and forests.
Finally, as someone noted, kinetic energy, which is the primary means of killing a tank is determined by mass x velocity squared. But, the mass of a long rod penetrator has little do with the bore of the gun. The penetrator is typically no more than 40mm in diameter and 500mm in length. This basic design changes very little due to bore size. The American 105mm rifled gun fired a penetrator almost the same size as the American 120mm gun, albeit at a lower muzzle velocity. So, the reality is that the only way to increase the killing power and ballistic stability of the kinetic energy penetrator (sabot round) is by increasing the velocity. Since the Russian 125mm gun cannot withstand the amount of propellant required to do this it is at a disadvantage. This was seen clearly during Desert Storm in 1991 when American M1's engaged T-72's. The T-72 consistently missed targets beyond 1500 meters, while the M1 was successfully engaging beyond 3000 meters (I had first round hits at 3400 meters)
/excerpt off
Finally, this response is from a tanker with extensive experience in russian tanks and is the foreign equivalent of the prev poster (a US master gunner)
/excerpt on
The overall tolerances of gun making quality are much less strict that those in west in general.
Objectively looking, however, I wouldn't consider the accuracy of 125mm gun as dramatically worse as you suggest. Most of the limitations confronted are brought by inferior FC, not the gun itself (this is particularly true with Iraq tanks, though very poor crews in western standard and woefully outdated ammunition, 30 years old protection standards etc. also affected to their bad overall appereance). The problems brought by 125mm gun accuracy are significantly present at ranges over 3000 meters, i.e. ranges that they're not able to engage nearly as effectively as western tanks due to limitations of FC anyway. Only at ranges beyond 2500 meters the grouping of 125mm is such that it can cause a significant number of misses over frontal profile of a tank (higher than 1.3 of 125 vs. higher than 0.5 of 120). A qualified crew can achieve a very good hit percentage even with elder russian guns and sights at ranges up to 2000m. Unqualified crews, as seen on Iraqi case, can easily miss at ranges of 500m, which shouldn't happen
/excerpt off
The catch in the above is that the western development of the 125 cannot be associated with data history based on russian legacy weapons platforms. (remember the mass production metallurgy and qualitative metallurgy issues).
I hope this clears up some things for everyone.
dabrownguy
New Member
- Thread Starter Thread Starter
- #77
Nice job. Good point. If think Russia is ahead in making better rounds.
Did you read all of Denils comments? Heres something interesting. gf you'll like it.
"As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit – and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration."
Thats pretty insane eh? I guess 25 years in research payed off. what do u think?
Did you read all of Denils comments? Heres something interesting. gf you'll like it.
"As the grooves on the inside of the barrel "grip" the projectile to spin it, they also slow it down) - not valid though. This FS-AP you are pointing out is the one with exposed cone. The AP fired from this barrel is a dual stage projectile. The cone is sealed in a condom type rubber around it with 3 burnable line seals. During travel through the barrel it heats up and burns out exposing the main cone on exit – and then separates the sabot jacket. So during travel it is as smooth as a smoothbore with a HIGHER velocity and hence a flatter trajectory, better accuracy and greater penetration."
Thats pretty insane eh? I guess 25 years in research payed off. what do u think?
so, are you saying that the three burnable seals are acting like disposable forms of wadding? thus there is a concatenating increase in pressure behind the shell and thus a higher terminal velocity?dabrownguy said:
I know the russians tried to sleeve ceramic linings but had no success, the germans also tried teflon lining as well. its an age old problem. The US has had problems with bore wear on its rail guns as well. - at a far higher degradation rate than any tank or arty barrel.
dabrownguy
New Member
- Thread Starter Thread Starter
- #79
This is interesting converstion. I guess so. India wouldn't be useing Arjun's rifled gun if it wasn't high velocity. That must be one of the reasons why Arjun costs 5.6 million eh?
Not sure if its possible to extrapolate this to a tanks main gun. But a few years ago I was involved with a project that looked at recoil management on artillery, the general barrel replacement process for a rifled barrel was 2-3 times higher than a smooth bore. (assuming same firing rate per minute and then averaged out until system failure)
So, not only are the initial costs nominally higher at purchase, but they are also higher throughout the life of the platform.
There are obviously some clear tactical benefits perceived in continuing to purchase a rifled bore over a smooth bore.
Its not always simple to say rifle is better than smooth, or vice versa.
Platform, ammo, threat, theatre of ops, logistical support, training etc all come into play
So, not only are the initial costs nominally higher at purchase, but they are also higher throughout the life of the platform.
There are obviously some clear tactical benefits perceived in continuing to purchase a rifled bore over a smooth bore.
Its not always simple to say rifle is better than smooth, or vice versa.
Platform, ammo, threat, theatre of ops, logistical support, training etc all come into play
- Status